What is MMA

In this chapter, the authors introduce the concept of MMA through reviewing the development of conventional absorbers. To illustrate the important operating mechanism, design process, and functionalization of the metamaterial absorber, they show the absorption relation of the absorber, impedance matching condition, equivalent circuit model, the evaluation of thickness, and oblique incidence condition in the first part. Then, they show the basic design method of the absorber, including parameter sweep method, equivalent circuit method, and deep learning method. Next, the planar integration strategy, vertical stacking strategy, and dispersive material strategy for broadband absorption bandwidth are discussed. In addition, they illustrate the tunable design of absorber, involving lumped element design method, thermal tunable design method, electrical tunable design method, mechanical tunable method, and reconfigurable tunable method. Finally, they talk about the basic engineering application of the metamaterial absorber in practical engineering application.